Oracle CPQ: Is there a way to detect/track when a row is added or a value is edited in an Array Set?

I have a line-level Array Set, "Other Charges" (otherChargesArrayset_c), with a child attribute others_c(Float). I need to detect whenever a user adds a new row or edits an existing value in this array set, so that I can trigger a recalculation and update a total attribute (totalOtherCharges_c). This must happen automatically, without a custom action button.

This worked fine with BML Logic added in a custom action button.

The calculation logic itself works correctly — when any normal header/line attribute change fires my auto-update formula, the total is computed and written correctly. The only thing I cannot achieve is detecting the array-set change itself.